Lightning-protector.



A. P. ROSENBERGER.

LIGHTNING PROTECTOR.

APPLIUATION FILED JAN. 2, 1908.

970,556. Patented Sept. 20, 1910.

BEST AVAILABLE COP ANDREW F. ROSENBERGEB, OF CHICAGO, ILLINOISLIGHTNING-PROTECTOR.

Specification of Letters Patent.

Patented Sept. 20, 1910.

Application filed January 2, 1908, Serial No. 408,895

1'0 all whom it may concern:

Be it known that I, ANDREW F. Rosenl, BERGER, a' citizen of the UnitedStates, residling at Chicago, in the county of Cook and State ofIllinois, have invented certain new and useful Improvements inLightning-Proteeters, of which the following :wspecilication.

2 This invention relates to improvements in lightning protectors, andrefers more specifieally to improvements in that type of protectorwherein the spark gap is provided for between carbon electrodes spacedapart loya dielectric.

A.mong the salient objects of the present invention are to provide aconstruction in which the spacing apart of the electrodes by thedielectric may be practically accomplished in a more accurate, reliableand less expensive manner than has heretofore been the case; to providea construction in which theparticles of carbon dust dislodged by thepassage oi cm-rent across the gap will he -more certainly prevented fromlodgmcnt in the gap; to provide a construction in which the spark gap isprovided {or along a liuc ol' practicz lly inapprtariable thickncss butol' considerable length as distinguished l'rom a spark gap in which lhcclot-trodes are spaced apart over av considerable area ol' approximatelyuniform distance of spacing, and to provide a construction which may hemade rapidly and by the use of labor of only mod- "erate skill andstill-secure reliable and accurate results. I 1

i The invention consists in the matters hcreinatter described andparticularly delincd in the claims. I

In'the accompanying dran'ing diigiirc l is a plan view of one practicaland p'reterred embodiment of the invention; Fig. 2 is an edge elevationofthe device shown in position set at ninety degrees out of the angularposition in which it is ordinarily used (the device as shown in Fig. 1being in correct position); Fig. 3 a cross sectional view taken on line3--3 of Fig. 2; Fig. 4t is an exploded View sh the relativearrangeinentot the dischrirgc electrodes.

Referring to the drawing, 1 designates a suitable base which is made ofporcelain or other suitable insulating material. Upon the base ismounted a conductor p ate :4, preferably of L-shape, one end tln reot'being arranged to rest flat upon the base, being extended radiallyoutward and connected with a binding stud 3, and the other end beingarranged to extend at right angles to the base and constituting asupport. against which two pairs of carbon electrodes, as 4, l, and 5,5, are arranged to rest. 'l'hat to say, the outstanding portion 2 ol theconductor plate 2 is common to both pairs of electrodes The two mcmlwrsof each pair of carbon electrodes are placcd t'acc to l'acc against eachother, and each pair is held yicldingly against the supporting plate 2by means of a corrcsptnnling plate spring, as (3 and 7; these platesprings being provided with base portions t3 and T, respectively,bent tolie llatwise upon the porcelain has and scveially connected at theirouter ends with terminal posts 8 and S). The outermost members and 5 ofthcpairs of electrodes are longitudinally i'oorcd to rcccirc thccorrcslmndiug spring lingers t3 and Ti so that the springs serve to holdthcsc clcclrodcs against lateral displaccmcul. but. as u ual inplolct'lol's ol this gcuclal typo, tlic pairs-of clcctrodcs may heslipped out cudwisc l'rom hctwccu the swings and opposed supportingplate.

lhrscribing now the essentially novel lcaturcs ot the device, it will benoted that each pair of electrodes is separated by a dielectric sheet,as it), prtl'erably athin sheet of mica. The dielectric, instead ofcovering the meeting surfaces oi the clectrodcs, is cut away hctwcen itsends and from one edge inwardly, as best indicated in 'l ig. 4, soas'toleave two opposed sur tacos, .11 and 12, bcl'wccli the electrodes12.

covered and constituting the spark gap bctween the two. 'lhcse opposedsurfaces which constitute the spark gap are divergent; orcr the entirearea of the gap, and, as best scen in Fig.3, the edge .13 of thedielectric l() is arranged coincident with the angle ol intersection oisaid gap surfaces. It "follows that. since the current will leap the gapsome place along the line of closest; approach between the twoelectrodes, where the latter are not covered by the dielectric,therefore the sparkis bound to leap. across or within the divergent gapand is most likely to occur along the eXposed edge '13 of thedielectric.

In practice I have found it mostpractical to first glue or otherwisesecure the sheet of dielectric to the face of one of the electrodes sothat it completely covers the latter and projects somewhat beyond theedges of the electrode all around, and I then grind away the dielectricand underlying surface of the carbon to produce the inclined spark gapsurface 11. When the two electrodes are thereafter assembled, theunrecessed or unground end portions of the recessed electrode fitfiatwise against the flat face of the opposed electrode and so determinethe angle of divergence between the two opposed surfaces whichconstitute the spark gap. With the parts thus constructed and assembledit .is obvious that whenever current asses from one electrode to theother it is bound to jump across some part of the divergent gap, andaccordingly, if the protector be arranged with the gaps openingdownwardly, as it should be in )ractice, the particles of carbondislodged y the discharge fall out of the gap and leave theap-insulation unimpaired when the discharge ceases. The construction isr such. that the effective separation of the electrodes in the ap isequal to the thickness of the sheet of dielectric, and this distance ofseparation is very uniform throughout the whole length of the spark gapalong the edge of thedielcctrica This is of "impoi'tance in securing aprotector which is certain to transmit the current at an approximatelyuniform predetermined voltage, and the construction is also important inthat it insures an ample area of opposed surfaces to take care of veryheavy discharges without impairing the protector.

The electrodes are preferably and usually covered by a casing to protectthem against the weather. In the preferred construction shown, athreaded thimble 14. provided with an out-turned or radial flange 14: issuitably secured to the base so as to surround the base portions of theelectrodes; this member being separated from the underlying portions ofthe springs 7 by an insulating washer 8 of mica or the like. A sheetmetal tubular cap '15 is fitted to screw upon the thimble 14, as shownclearly in the drawing; this cap being provided with vent apertures inits upper end to 'wrmit gases formed-by discharges to escape.

As will be well understood by those familiar with-this art, theparticular device illustrated is adapted to protect two lines byproviding a spark gap between each and a common return or ground; theterminals 8 and. 9 being fortwo-line wires and the terminal 3 for thecommon returnor ground. Willle' I have herein shown a preferredconstruction of the clectrpdes, yet it is to be understood that theinvention may be i'it-herwisc embodied.

I claim as my invention:

1. in a protector, the combination with suitable electrical connections,of a pair of coveredponvergent surfaces and a dielectricof greaterinsulating resistance than air separating said electrodes at their placeof nearest approach.

in a protector, a pair of GIBUMCOUBS having parallel contacting portionsand divergent gap surfaces and a sheet of'insulating material interposedbetween and covering said contacting portions of the electrodes andarranged with its edge coincident with the intersecting angle of thegap.

4. [n a protector, an electrode block one side of which has the form ofa plane surface except for a recess extending from one edge inwardly,said recess having an inclined bottom and being of decreasing depth fromsaid edge inwardly and terminating short-of the opposite edge, a sheetofinsulating material entirely covering the unrccesscd portion ofsaidplane surface of the electrode and cut out to register with the saidrecess, and a second electrode block provided with a plane surfacearranged in" bearing with said insulating sheet, whereby a divergent airgap is formed between said (lttl rodcs.

5. In a protector, an electrode block, one side of which has the form ofa plane sur+ face except for a recess extending from one edge innardly,said recess having an inclincd bottom and being of decreasing depth fromsaid edge inwardly andterminating short of the opposite edge, a sheet ofinsu lating material adherent to and entirely covering the unreccssedportion of said plane surface of the electrode and cut out to registerwith the said recess, and a second electrode block provided with a planesurface arranged'in bearing with said insu lating sheet, whereby adivergent air gap is formed between said electrodes.

(3. In aruotector, an electrode block, one side of which has the form ofa plane surface except for a recess extending from one edge invardly,said recess having an inned bottom and being of decreasing depth fromsaid edge inwardly and termihating short of the opposite edge, a sheetof insulating material adherent to and entirely covering the unrecessedportion stand plane surface of the electrode and cut out to I registerwith said recess, a second electrode 7. A spark gap device for lightningresters, comprising a plurality of carbon block provided with a planesurface an i plates spaced apart by an insulating washer ranged inhearing with said insulating 5 sheet, whereby a divergent air gap isformed between said electrodes, a conductor support engaging one side ofthe pair of elecvtrorles and a spring, bearing yieldingly against theopposite side of said pair.

and having cut away portions to form an are expanding chute.

ANDRElV F. ROEENBERGER. \Vitnesses EMILLE Rose, E. L. BELKNAP.

DISCDILAIMEIBL Lronrnmo'lno'rncron. Patent 70.556r-u1l1'2d7t10 F.Rosenberg/er, Chicago, Ill.

Disclaimer filed February "6 1912. hr the trustee.

dated September 20, 1914').

Charles- J Schmidt. Enters this disclaimer To claims 1; 2, and, 7, whichare as follows: v 1. In a protector, the comliiination with suitableelectrical connections, of a pair of electrodes provided with opposedspark gap surfaces which converge, and a solid dielectric interposedbetween the most contiguous portions of said electrodes and arranged todivert passing discharges across the gap between said convergentsurfaces.

2. In a. protector, the combination with suitable supports and terminalconnections, of a pair of electrodes having opposed uncovered convergentsurfaces and a dielectric of greater insulating resistance than airseparating said electrodes at their place of nearest approach. I

7. A spark gap device for lightning arresters, comprising a plurality oicarbon plates spaced apart by an insulating Washer and having cut-awayportions to form an are expanding chute.

[Ofict'ol Gazette, February 13, 1912.]

